1. Field of the Invention
This invention relates to combination burners for oil and gas and more particularly to structure for suppressing the noise attendant upon the entrance of the air for combustion and the combustion noise.
2. Description of the Prior Art
The noise attendant upon the operation of gas and oil burners is objectionable to persons in surrounding areas, and prolonged exposure may result in loss of hearing of operating personnel.
Various proposals have been made to reduce the noise level but none of these has proven wholly satisfactory.
In the U.S. Pat. No. 3,907,489, to Santisi, an inspirating gas burner is shown in which the pressure of the combustible gas is utilized to entrain the primary air, the primary air being admitted through openings facing toward the furnace and passing rearwardly and forwardly in a labyrinth path for inspiration by high pressure combustible gas into a bell for delivery into the furnace. The primary air in its rearward and forward passage into the bell is surrounded by a lining of sound absorbing material. The admission of the primary air is controlled by an axially adjustable shutter. Secondary air for combustion, controlled by another axially adjustable shutter, is not shielded as to noise.
It has heretofore been proposed to provide combination burners, the U.S. Pat. No. 2,918,966 being illustrative. No provisions are shown in this patent for noise suppression.